How does c++ determine whether an integer literal fit int type or not?

Question

I know the standard says if the integer literal does not fit the int, it tries unsigned int, and so forth, per section 2.14.2 Table 6 in the standard.

My question is: what's the criteria to determine it fits or not?

Why do both std::is_signed<decltype(0xFFFFFFFF)>::value std::is_signed<decltype(0x80000000)>::value gives false. Why don't they fit in int? 0x80000000 has the same bit representation as signed -1 signed -2147483648.

Answer 1

You don't need to look at "bit representation" to check if the number fits or not.

Assuming sizeof(int) == 4, int can represent numbers from -2³¹ to 2³¹-1 inclusive.

0x80000000 is 2³¹, which is 1 larger than the maximum value.